ESS THD ‘Hump’ Investigation

[Blur]

From what I can tell there is compensation needed for the THG Hump that comes before the actual DAC chip. If we look at the what Benchmark has laid out on their site you can see the block diagram:

https://benchmarkmedia.com/blogs/application_notes/dac3-introducing-the-new-es9028pro-converter

As you can see after the Over Sampling phase they run the signal into a Channel Map and THD Compensation routine. All of this happen before the chip. I'm not sure exactly what Benchmark does, but could it be some sort of balanced differential signal so the THD subtracts instead of adds?

 

[JohnYang1997]

From what I can tell there is compensation needed for the THG Hump that comes before the actual DAC chip. If we look at the what Benchmark has laid out on their site you can see the block diagram:

https://benchmarkmedia.com/blogs/application_notes/dac3-introducing-the-new-es9028pro-converter

As you can see after the Over Sampling phase they run the signal into a Channel Map and THG Compensation routine. All of this happen before the chip. I'm not sure exactly what Benchmark does, but could it be some sort of balanced differential signal so the THD subtracts instead of adds?

Maybe it will help your understanding by searching a bit for open loop control system theory. Wikipedia is good enough for simple understanding.

 

[Miska]

From what I can tell there is compensation needed for the THG Hump that comes before the actual DAC chip. If we look at the what Benchmark has laid out on their site you can see the block diagram:

https://benchmarkmedia.com/blogs/application_notes/dac3-introducing-the-new-es9028pro-converter

As you can see after the Over Sampling phase they run the signal into a Channel Map and THD Compensation routine. All of this happen before the chip. I'm not sure exactly what Benchmark does, but could it be some sort of balanced differential signal so the THD subtracts instead of adds?

That is block diagram of the ESS Sabre, all that is inside the chip and thus applies to all designs using the same chip... You can configure the THD compensation on/off, and it makes pretty huge difference actually. But it is separate from the IMD hump.

 

[Blur]

Just a feedback mechanism then, eh?

 

[deafenears]

@Ben1987 shares how he fixed the ESS hump on the SGD1 and LA-QXD1.

 

[PPP]

I doubt the "hump" is from the I/V stage. If the hump would be an issue when approaching the 0dB SPL I might understand that an opamp with a better current handling might help, but in this case the hump is somewhere in the middle.

However, maybe there is an explanation regarding the hump and the I/V stage, just that I'm unable for the moment to dig one. Perhaps somebody else might explain this better, thanks!

Ben’s analysis confirms the hump is only related to the I V stage.

 

[trl]

Ben’s analysis confirms the hump is only related to the I V stage.

Great, do you have the exact post# with explanations and what opamps were tested?

It would be nice to know what exact spec of the "winning opamp" is the one that cares about this thump (output current?, input offset? a.s.o.)

Thank you!

 

[SpyB]

Great, do you have the exact post# with explanations and what opamps were tested?

It would be nice to know what exact spec of the "winning opamp" is the one that cares about this thump (output current?, input offset? a.s.o.)

Thank you!

https://www.audiosciencereview.com/...ow-to-fix-ess-hump-on-sgd1-and-la-qxd1.10502/

 

[trl]

Thanks for sharing @SpyB, seems that adjusting the IV resistor and the LPF to an increased value did resolved the issue: "The capacitance value is set at 220pF and the resistance value is set at 51R".

Probably makes no sense to keep this thread animated, given that most of the data is on the thread posted by SpyB.

 

[solderdude]

Indeed in the end, as always, it is not the DAC chip that is at fault but incorrect application of the components around it.
Makes sense as there are DACs using the same chip and do not have the IMD hump.
Kuddo's for @Ben1987 (and those that helped him) to be so forthcoming with the path he took and showing/sharing the results.
He could have kept it to himself.

 

[Windofrce]

Is it audible after all? Should I be worried about buying Khadas Tone Board for example and use it with my Atom AMP?

 

[JohnYang1997]

Is it audible after all? Should I be worried about buying Khadas Tone Board for example and use it with my Atom AMP?

It can be audible or not. But are you bothered by the sound? If not, I don't think there's a need to figure that out. So enjoy the music.

 

[gvl]

Is it audible after all? Should I be worried about buying Khadas Tone Board for example and use it with my Atom AMP?

I cannot detect it with the KTB. If it is audible it will be at very high volumes, you ears will likely start to distort earlier.

 

[Windofrce]

I cannot detect it with the KTB. If it is audible it will be at very high volumes, you ears will likely start to distort earlier.

Thanks. That is great to know.

 

[confucius_zero]

Is it audible after all? Should I be worried about buying Khadas Tone Board for example and use it with my Atom AMP?

Definitely the reason why I disliked the Loxjie D10 over the "humpless" Topping D10, D30, Sonata HD Pro, Meizu Pro DAC which I I bought thx to this website... so yes it's audible. The feeling of uncontrolled upper-mids to treble ringing through your skull despite the high clarity.

This is what Sabre glare is all about.

 

[gvl]

Sabre glare, if it's a thing, is people unable to deal with clean and dynamic sound from ESS chips when they switched from inferior offerings. It has nothing to do with the hump.

 

[andreasmaaan]

Is it audible after all? Should I be worried about buying Khadas Tone Board for example and use it with my Atom AMP?

There's no way it's audible IMHO.

Listen to a signal that's been passed through an ESS DAC eight times (was this in fact a Khadas Tone Board - I can't recall?). Anyway, if you can hear the alleged glare, it may be audible. Otherwise, it 100% is not.

EDIT: oops, left out the link.

 

[confucius_zero]

they switched from inferior offerings

unfortunately, I own equal or higher humpless sinad dacs to know it's definitely audible. Sorry!

 

[BYRTT]

Is it audible after all? Should I be worried about buying Khadas Tone Board for example and use it with my Atom AMP?

I cannot detect it with the KTB. If it is audible it will be at very high volumes, you ears will likely start to distort earlier.

Same here for KTB i cannot detect it for more than a year, and lately compared it to ADI-2 Pro fs did not help, my ears feels good as new but admit they from 1964 : )

Definitely the reason why I disliked the Loxjie D10 over the "humpless" Topping D10, D30, Sonata HD Pro, Meizu Pro DAC which I I bought thx to this website... so yes it's audible. The feeling of uncontrolled upper-mids to treble ringing through your skull despite the high clarity.

This is what Sabre glare is all about.

Think we had it before sorry : ) in my opinion you cant for sure couple hump with the anoying thing disliked for your Loxjie D10 experiense, fault there could have been from factory for example wrong value one component or a missing component as a compensation capacitor and chips can sit there oscilate up in mHz that some can detect and others not, happy you report and share product experiense thanks but unhappy you try point out or bind the technical reason without really have the proof.

 

[confucius_zero]

i cannot detect it for more than a year,

awesome, you saved money then! sadly I could so I had to resort to other things in the vast selection of humpless measured dacs of this website.